ElkRP2 update 2.0.24 can't connect to XEP

So I installed this new M1 with XEP, was able to connect with RP2 ver 2.00.016 and set system up this morning.  This afternoon I tried to connect and got error that RP2 could not connect, needed to update RP2.  I could still connect to other M1s.
 
I updated RP2 to 2.0.24.  When attempting to connect to the new M1, I received notification of difference between db and system of something (from memory) like "M1XEP update".  Assuming new features from RP2 update, I chose to send to system.  XEP reboot was required.  I can no longer connect to this system.  Am able to connect to the other M1s still.
 
I rebooted the M1, the XEP, the PC to no avail.  When I "find" in setup, RP can see the M1 with correct MAC and IP.
 
Any ideas?

Did you ever change the RP Access Code?

No, I did not change the RP access code.

So, if I read the above correctly, you can use ElkRP (2.0.24) and scan for XEP's, as well as locate yours... but not connect to it?
 
I don't think I've ever been able to see an XEP that I couldn't connect to...

Have you scanned the network for the MAC of the XEP? Could've gone DHCP and gotten a new address from your equipment.
 
How is/was your network configured? DHCP, static, DHCP reserved?

DELInstallations said:

Have you scanned the network for the MAC of the XEP? Could've gone DHCP and gotten a new address from your equipment.
 
How is/was your network configured? DHCP, static, DHCP reserved?

Click to expand...

 
Not sure about the latter, but this was in the OP...
 

Piasa said:

I rebooted the M1, the XEP, the PC to no avail.  When I "find" in setup, RP can see the M1 with correct MAC and IP.

 
Any ideas?

Click to expand...

When I "find" the XEP in RP, the MAC and IP address are correct, and the same values they were when I was able to get a response.

The XEP shows up as "connected" in my local router.  I am able to ping it from my PC.  Both of these signs of connectivity are present whether or not the XEP is connected via its serial cable to the M1.  Is there some diagnostic which addresses communication between the M1 and the XEP?

Try this. 
 
d:\work>ftp 172.16.1.199   (use YOUR xep's ip address)
Connected to 172.16.1.199.
220 NET+OS 6.3 FTP server ready.
User (172.16.1.199none)): ^C
d:\work>
 
This can tell you if the XEP is responding at some level other than ElkRP.
 
You should also try connecting it and your PC to a hub/switch instead of the router.  This will take the router out of equation.